The second of two programmes, in which Kate Humble and a team of experts and explorers visits the hottest place on the planet, sees them venturing into the Danakil Desert in northern Ethiopia to investigate the geology of the area and meet the people and animals who survive in this harsh environment. The group faces its biggest challenge yet, descending into the the crater of Erte Ale volcano, which holds a swirling lake of boiling lava. BBC1 heads back to Africa at 9.00pm for The No.1 Ladies' Detective Agency. Precious unearths some shocking truths during her efforts to establish whether Mrs Curtin's son, who has been missing for 10 years, is dead or alive. Meanwhile, Mma Makutsi takes on the case of the Kgale Hill break-ins in the hope of proving her worth as an assistant detective rather than just a secretary. Guest starring ER's CCH Pounder.